• Title/Summary/Keyword: Loss Estimation

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Case study of volume loss estimation during slurry tbm tunnelling in weathered zone of granite rock (화강풍화대를 통과하는 슬러리 TBM의 체적손실 산정에 대한 사례 연구)

  • Park, Hyunku;Oh, Ju-Young;Chang, Seokbue;Lee, Seungbok
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.1
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    • pp.61-74
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    • 2016
  • This paper presents a case study on the ground settlement and volume loss estimation for slurry pressure balanced shield TBM tunnelling in weathered zone of granite rock. Settlement at each stage of shield tunnelling was analyzed and the volume losses and settlement trough factors were estimated from observations. In addition, using the existing volume loss evaluation method in literature, volume losses were estimated considering ground properties and actual driving parameters. Most of ground settlement occurred during passage of shield skin passage and after backfill grouting, and the measured total volume loss and trough curves appeared to coincide with literature. Shield and tail loss obtained from field measurement were found to be around 90% and 60% of the predictions, where tail loss indicated larger deviation than shield loss.

Sampling Based Approach to Hierarchical Bayesian Estimation of Reliability Function

  • Younshik Chung
    • Communications for Statistical Applications and Methods
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    • v.2 no.2
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    • pp.43-51
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    • 1995
  • For the stress-strengh function, hierarchical Bayes estimations considered under squared error loss and entropy loss. In particular, the desired marginal postrior densities ate obtained via Gibbs sampler, an iterative Monte Carlo method, and Normal approximation (by Delta method). A simulation is presented.

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Bayesian Reliability Estimation for the Rayleigh Model under the Censored Sample with Incomplete Information

  • Kim, Yeung-Hoon
    • Journal of the Korean Data and Information Science Society
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    • v.6 no.1
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    • pp.39-51
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    • 1995
  • This paper deals with the problem of obtaining some Bayes estimators of Rayleigh reliability function in a time censored sampling with incomplete information. Using the priors about a reliability function some Bayes estimators are proposed and studied under squared error loss and Harris loss.

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Operational Risk Measurement of Financial Institutions via AHP (AHP 분석을 이용한 금융기관 운영리스크 측정)

  • Choi, Seung-Il
    • Korean Management Science Review
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    • v.28 no.3
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    • pp.73-82
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    • 2011
  • Basel II advanced measurement approaches for operational risk need to estimate the frequency and severity distribution of operational losses. Due to lack of internal loss data, the estimation is impossible in many cases and so external loss data might be used by scaling on asset or gross income. To get around lack of loss data, scenario analysis combined with loss distribution approach can be useful in calculating the capital charge of operational risk. However, scenario based loss distribution approach requires much time and effort. Instead we may apply the analytic hierarchy process to measure operational risk of financial institutions. The analytic hierarchy process combined with loss distribution approach is to estimate the capital charge of operational risk in other areas based on the operational VaR in an area with sufficient loss data. AHP provides a tool for timely measurement of operational risk in this rapidly changing global environment.

The Iron loss Estimation of IPMSM According to Current Phase Angle

  • Cho, Gyu-Won;Kim, Dong-Yeong;Kim, Gyu-Tak
    • Journal of Electrical Engineering and Technology
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    • v.8 no.6
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    • pp.1345-1351
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    • 2013
  • Variable iron loss as function of current phase angle of Interior Permanent Magnet Synchronous Motor(IPMSM) was calculated through Curve Fitting Method(CFM). Also, a magnetic flux density distribution of iron core according to current phase angle was analyzed, and an iron loss calculation was performed including harmonic distortion. The experiment was performed by production of non-magnetizing model for the separation of mechanical loss, and the iron loss was calculated by the measurement of input using power analyzer and output power using dynamometer. Some error was generated between experimental results and calculation value, but an iron loss diminution according to current phase angle followed a same pattern. So, errors were generated by measurement, vibration, noise, harmonic distortion loss, etc.

Power and loss characteristics of PMSM/G with double-sided Halbach magnetized rotor (양측식 Halbach 자화 회전자를 갖는 영구자석 동기 전동발전기의 출력 및 손실 특성)

  • Jang, Seok-Myeong;You, Dae-Joon;Choi, Sang-Kyou
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.723-724
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    • 2008
  • The rotational loss is one of the most important problems for the practical applications of PM synchronous motor/generator. This rotational loss is divided as the mechanical loss by windage and bearing and iron loss by hysteresis loop and eddy current in the part of the magnetic field. So, In this paper, a double-sided PMSM/G without the iron loss is designed by analytical method of the magnetic field and estimation of the back-EMF constant represented as the design parameter. This design model consists of the double-sided PM rotor with Halbach magnetized array and coreless 3-phase winding stator. The results show that the double-sided PMSM/G without iron loss can be applicable to the required system without the rotational loss.

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Effect of Channel Estimation Error on Capacity of MIMO Systems (MIMO 시스템의 채널 용량에 대한 채널 추정 오차의 영향 분석)

  • 함재상;심세준;이충용;박현철;홍대식
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.41 no.8
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    • pp.63-68
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    • 2004
  • The capacity of MIMO systems is numerically analyzed when channel estimation error exists. The analysis shows that the capacity is influenced by Mean Square Error (MSE) as well as average Signal to Noise Ratio (SNR). Furthermore, in this paper we present the standard selecting a channel estimator suitable to a system owing to get a tolerable channel estimation error in a given average SNR and channel capacity loss. The simulation results show that the tolerable MSEs for 1 bps/Hz capacity loss are about 10$^{-2}$ and 10$^{-4}$ at n dB and 40 dB average SNR, respectively.

Monocular Camera based Real-Time Object Detection and Distance Estimation Using Deep Learning (딥러닝을 활용한 단안 카메라 기반 실시간 물체 검출 및 거리 추정)

  • Kim, Hyunwoo;Park, Sanghyun
    • The Journal of Korea Robotics Society
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    • v.14 no.4
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    • pp.357-362
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    • 2019
  • This paper proposes a model and train method that can real-time detect objects and distances estimation based on a monocular camera by applying deep learning. It used YOLOv2 model which is applied to autonomous or robot due to the fast image processing speed. We have changed and learned the loss function so that the YOLOv2 model can detect objects and distances at the same time. The YOLOv2 loss function added a term for learning bounding box values x, y, w, h, and distance values z as 클래스ification losses. In addition, the learning was carried out by multiplying the distance term with parameters for the balance of learning. we trained the model location, recognition by camera and distance data measured by lidar so that we enable the model to estimate distance and objects from a monocular camera, even when the vehicle is going up or down hill. To evaluate the performance of object detection and distance estimation, MAP (Mean Average Precision) and Adjust R square were used and performance was compared with previous research papers. In addition, we compared the original YOLOv2 model FPS (Frame Per Second) for speed measurement with FPS of our model.

Quality Estimation of Net Packaged Onions during Storage Periods using Machine Learning Techniques

  • Nandita Irsaulul, Nurhisna;Sang-Yeon, Kim;Seongmin, Park;Suk-Ju, Hong;Eungchan, Kim;Chang-Hyup, Lee;Sungjay, Kim;Jiwon, Ryu;Seungwoo, Roh;Daeyoung, Kim;Ghiseok, Kim
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.28 no.3
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    • pp.237-244
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    • 2022
  • Onions are a significant crop in Korea, and cultivation is increasing every year along with high demand. Onions are planted in the fall and mainly harvested in June, the rainy season, therefore, physiological changes in onion bulbs during long-term storage might have happened. Onions are stored in cold room and at adequate relative humidity to avoid quality loss. In this study, bio-yield stress and weight loss were measured as the quality parameters of net packaged onions during 10 weeks of storage, and the storage environmental conditions are monitored using sensor networks systems. Quality estimation of net packaged onion during storage was performed using the storage environmental condition data through machine learning approaches. Among the suggested estimation models, support vector regression method showed the best accuracy for the quality estimation of net packaged onions.

A Study of Shield TBM Tunnelling-induced Volume Loss Estimation Considering Shield Machine Configurations and Driving Data (쉴드 TBM의 장비 형상 및 굴진 데이터를 고려한 체적손실 산정 연구)

  • Park, Hyunku;Chang, Seokbue;Lee, Seungbok
    • Tunnel and Underground Space
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    • v.25 no.5
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    • pp.397-407
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    • 2015
  • Estimation of shield TBM tunnelling-induced volume loss is of great importance for ground settlement control. This study proposed a simple method for evaluation of volume loss during TBM tunnlling, which is able to take into account of shield machine configurations and main driving data in calculation. The method was applied to analyze the tunnelling cases with earth pressure balanced and slurry pressure balanced shiled TBM, and mostly, reasonable agreements with monitoring results were found. Additional discussions were made for some disagreements.